The travails of Hillary Rodham Clinton - criticism of her activism as well as questions about her credibility in the Whitewater and “Travelgate” affairs - have reminded Americans that the proper role for a first lady remains an unsolved national puzzle. Historians note that resentment of the political influence often exerted by this unelected leader goes back to the dawn of the republic. Yet the 20th- century rise of the career woman has highlighted a built-in tension between the traditional duties of the White House hostess and the modern role for an independent woman. The 1996 presidential race, in which both prospective first ladies - Mrs. Clinton and Elizabeth Dole - are accomplished professionals, marks a turning point in this historic debate.